Cleaning the inside of the fuel tank

[sp838]

Finally getting around to installing the later model tank on my '01. I want to line the inside of the tank with epoxy sealant in order to prevent ethanol damage. I was planning on sloshing some acetone around in there, in order to clean it. Just wanted to make sure before I did that, don't want to use acetone on the plastic if there will be a problem.

 

So, acetone + nylon tank, yea or nay?

 

Thanks!

[GuzziMoto]

I don't remember if I used acetone or not, I think I did. But the more important thing I did was to use a pound if drywall screws (coarse) to rough up the inside of the tank.

Acetone should not affect nylon.

[sp838]

Cool. Yeah, I was definitely going to do that too. Rough up the inside with screws, rinse with acetone, repeat once, blow out interior with compressed air, let it air dry, then coat.

[Scud]

Cool. Yeah, I was definitely going to do that too. Rough up the inside with screws, rinse with acetone, repeat once, blow out interior with compressed air, let it air dry, then coat.

 

Would you mind posting some more detail about this procedure?  It would be helpful to know things such as:

1. what do you need to remove (fuel door, petcock, etc.),
2. exactly what coating should be used - and how it is applied.

I've seen a number of posts with concerns about the effect of ethanol on the plastic tanks. It occurred to me that some sort of lining would prevent damage, but I hadn't done any research into it yet. It would be great to have a "how to" for this.

[docc]

For sure, the (byproducts of) ethanol in the fuel are not Nylon (polyamide) friendly, and there have been various attempts to seal the PA tanks. It seems to me (having used the typical 2-part epoxy for metal tanks) that the coating would have to be a bit flexible to accommodate the polyamide.

 

No doubt, keeping your ethanol in glass seems the best solution. Store until ready for consumption!

[sp838]

I am going to be using the tank sealer from Caswell Plating. It has been very favorably recommended and according to my research is the best product out there for this. I have heard only bad things about Kreem. It is basically a two part epoxy, and as docc says, it remains flexible after hardening which is a good thing for us plastic tank people.

 

I will try to document the process when I have some hands free. The basic idea is, remove all the hardware, protect the paint with tape/plastic wrap, rough up and thoroughly clean out the inside of the tank, protect threaded holes, plug everything up, and fill the tank with the epoxy through the filler hole. Plug the filler hole, then rotate the tank to coat the entire interior surface. Drain the excess, make sure any holes that need to be clear a re clear by poking them through, and let it cure. I found a number of good videos on YouTube by searching for "Caswell Plating tank sealer".

[Scud]

Thanks - I just did the search as you recommended. In doing so, I happened upon another thread on this forum, which is worth reading. It's about the failure of the Caswell system - but with some ideas about making sure it does work.

 

http://www.v11lemans.com/forums/index.php?showtopic=16928

[GuzziMoto]

There are people who have had good success with the Caswell coating and people who have had bad luck with it. As with any coating system, proper prep and application is key to success.

So far my luck with it has been good.

[sp838]

Thanks for posting that link Scud. As GuzziMoto says, the key appears to be proper prep of the inside of the tank to help the epoxy adhere. Also, reading that old thread, it sounds like it failed because it wasn't applied evenly. The thicker areas were fine, the thinner areas lifted. I'm wondering now if I should blast the interior, instead of just shaking it around with some drywall screws... Another idea might be to actually cut cross hatch lines into the inner surface with a cutting implement of some sort, though that would be hard to do with the only access being through the filler hole and the hole for the fuel pump and filter. I wonder what other methods to roughen the interior might work?

[Scud]

 I wonder what other methods to roughen the interior might work?

 

In addition to previous suggestions, you could probably get in there with a sanding flap wheel on a flexible shaft (electric motor), or a sanding sponge on a stick (manual). 

[sp838]

Yeah, the openings are a little small for that. I am going to blast the interior as best I can. I'll do the shake-it-with-drywall-screws routine afterwards. That should do it.